Patent GB-443298-A (GB)
Title: Improvements in or relating to the finishing of leather footwear
IPC: G05D13/00
Filed: 1934-08-28
Abstract: Footwear made of non-finished or only partially finished leather is treated with emulsions containing polymerization products of unsaturated organic compounds, for example poly-vinyl or poly-acrylic compounds.  Pigment and, or, soluble organic dyes may, if desired, be added to give any desired colour to the footwear at the time of purchase.  Other additions, such as softeners, oils, wetting agents or protective colloids may also be made to the emulsions  The emulsions may be aqueous emulsions containing ammonia or similar alkaline-reacting substances, and they may be applied, e.g. by brushing, in several coats, which may be of the same or of different colours and which may contain different polymerization products. Suitable examples of polymerization products are poly-vinyl esters, polymers of acrylic acid and their esters or polymers of homologues of these compounds.  These compounds in the solid condition are stated to be tenacious, elastic and resistant to water and the like. Softeners, such as tricresyl phosphate or castor oil, oils such as oil of turpentine, wetting agents such as alcohol, protective colloids such as rubber latex or tragacanth, gloss-imparting agents such as shellac and albumin, or, if desired, several of these mixtures, as well as drying oils, may be added to the emulsions.  The emulsions may be free from organic solvents or may, if desired, also contain relatively small quantities of organic liquids.  Aqueous emulsions may be prepared from suitable starting materials, such as vinyl acetate, acrylic acid, acrylic acid methyl or ethyl esters, meta-acrylic acid esters and the like, or mixtures of these by known methods, e.g. by heating in the presence of polymerization accelerators.  The polymerization need not be carried to completion but only to the point of formation of more or less viscous intermediate products from which the aqueous emulsions may be prepared.  The emulsions, before they are applied, may be subjected to an artificial or natural ageing process, e.g. by allowing them to stand for some time, if desired, at a raised temperature, say 40 to 50 DEG  C.  Alkaline reacting substances, such as ammonia, may be added.  In one example, 100 parts of a commercial aqueous emulsion of a polymer of acrylic acid derivatives are treated with 5 parts of concentrated aqueous ammonia, allowed to stand for three days at 50 DEG  C. and then mixed with 40--100 parts of a black pigment finish such as is usually used for dressing black leather.  Several coats of this may be brushed on to shoes made of non-finished leather and a final coat of an emulsion of the polymer without colouring matter may then be applied.  The toe cap may be brushed over two or three times with an emulsion of a poly-vinyl compound, containing no colouring matter, or colour-containing or colour-free solution of chlorinated rubber with, if desired, an addition of castor oil, may be used.  In a further example, shoes are treated with a finish prepared by mixing 100 parts of a 25 per cent aqueous emulsion of polymers of acrylic acid esters with 100 parts of a colouring solution containing 1--2 per cent of a black aniline dye and the same quantity of lampblack pigment.  1 per cent of ammonia, 0,5 per cent of shellac, 0,3 per cent of turkey red oil and, if desired, small quantities of xylene or other organic solvents, may also be added.  The colouring solution is preferably subjected, before its addition to the emulsion, to a boiling down treatment.  Two or three coats are employed, each coat being allowed to dry before the next is applied.  Specification 302,627, [Class 17 (ii)], is referred to.